You're assuming the knew who they were working for. The USG claims they destroyed evidence and obstructed justice.
> The charges against Miller and Taylor pertain to their alleged obstruction of justice, including by destroying evidence, after they were approached by agents with the Federal Bureau of Investigation (FBI) and asked about their procurement and dissemination of sensitive and confidential information from a restricted federal law enforcement database regarding U.S.-based dissidents from the PRC. This information was used by Liu and Sun in the transnational repression scheme. Both Miller and Taylor were arrested pursuant to a criminal complaint in June 2022.
It sounds like they provided information to the DHS agents from a protected database. Then when they figured out who they had provided this information to, tried to destroy the evidence of their involvement.
> The charges against Miller and Taylor pertain to their alleged obstruction of justice, including by destroying evidence, after they were approached by agents with the Federal Bureau of Investigation (FBI) and asked about their procurement and dissemination of sensitive and confidential information from a restricted federal law enforcement database regarding U.S.-based dissidents from the PRC. This information was used by Liu and Sun in the transnational repression scheme. Both Miller and Taylor were arrested pursuant to a criminal complaint in June 2022.
It sounds like they provided information to the DHS agents from a protected database. Then when they figured out who they had provided this information to, tried to destroy the evidence of their involvement.